Retrievable plug system and methods of use

Abstract

Apparatus and method for a retrievable plug in coil tubing. A plug is disposed within a tubing and is set within the tubing by an anchoring element placed in gripping engagement with the tubing. The plug also has seal elements disposed therein that are placed in sealing engagement with the tubing. An orientation element on the plug positions the plug within the tubing with respect to the seam of the tubing.

1. A plug assembly for use in a tubing, wherein the tubing has an inner surface along which a longitudinal seam extends, comprising:
 an anchoring element operable to secure the plug assembly within the tubing, wherein the anchoring element is extendable from the plug assembly at a first circumferential position to engage the inner surface of the tubing at a location spaced apart from the seam; 
 a seal element operable to create a sealing engagement between the plug assembly and the inner surface of the tubing; and 
 an orientation element configured to engage the seam and positioned on the plug assembly at a second circumferential position that is different from the first circumferential position; 
 wherein the spacing between the first and second circumferential positions is great enough such that when the orientation element engages the seam, the anchoring element engages the inner surface of the tubing but not the seam. 
 
   
   
     2. The plug assembly of  claim 1  wherein said orientation element comprises a key, wherein said key is operable to catch said seam. 
   
   
     3. The plug assembly of  claim 2  wherein said key and said anchoring element are located on opposed circumferential sides of said plug assembly. 
   
   
     4. The plug assembly of  claim 2  wherein said orientation element comprises a mule shoe operable to guide the plug assembly during insertion into said tubing, wherein said mule shoe is positioned below said seal element and below said anchoring element. 
   
   
     5. The plug assembly of  claim 4  wherein said mule shoe is characterized by a helical outer surface, and wherein the helical outer surface is further characterized by a helical groove. 
   
   
     6. The plug assembly of  claim 5  wherein said helical groove engages said seam. 
   
   
     7. The plug assembly of  claim 5  wherein said helical groove and said anchoring element are located on opposed circumferential sides of said plug assembly. 
   
   
     8. The plug assembly of  claim 1  wherein said seal element comprises a compressible seal member. 
   
   
     9. The plug assembly of  claim 8  wherein said seal member comprises a rubber compound with a 50 durometer hardness or less. 
   
   
     10. The plug assembly of  claim 1  wherein said anchoring element comprises at least one radially expandable slip for engaging the inner surface of the tubing. 
   
   
     11. The plug assembly of  claim 1  wherein said seal element is located below said anchoring element. 
   
   
     12. The plug assembly of  claim 1  wherein said plug assembly further comprises an anti-setting element operable to prevent said anchoring element from radially expanding until said plug reaches the desired location within said tubing. 
   
   
     13. The plug assembly of  claim 1  wherein said plug assembly further comprises an anti-setting element operable to prevent said anchoring element from radially expanding while said plug assembly is removed from said tubing. 
   
   
     14. The plug assembly of  claim 1  wherein said anchoring element is mechanically activated. 
   
   
     15. The plug assembly of  claim 1  wherein said anchoring element is hydraulically activated. 
   
   
     16. The plug assembly of  claim 1  wherein said plug assembly is retrievable from said tubing, and wherein said anchoring element is mechanically releasable by operation of a shear member. 
   
   
     17. A method of locating a longitudinal seam in a tubing, comprising:
 providing an orientation body; 
 disposing an orientation key on the orientation body, wherein the orientation key protrudes radially with respect to the orientation body; 
 providing a centralizing ring for aligning the orientation body with a longitudinal axis of the tubing; 
 providing an orientation spring for exerting an outward radial force on the orientation key, thereby causing the orientation key to engage the inner surface of the tubing; and 
 inserting the orientation body into the tubing; and 
 rotating the orientation body within the tubing until the orientation key engages the longitudinal seam. 
 
   
   
     18. A method of plugging a tubing, wherein the tubing has an inner surface characterized by a longitudinal seam, comprising:
 providing a retrievable plug comprising:
 an anchoring element extendable from the plug at a first circumferential position to engage the inner surface of the tubing at a location spaced apart from the seam; 
 a seal element disposed on the plug, wherein the seal element is compressible between a relaxed position and a radially expanded position; and 
 an orientation element configured to engage the seam and positioned on the retrievable plug at a second circumferential position that is different from the first circumferential position; 
 wherein the spacing between the first and second circumferential positions is great enough such that when the orientation element engages the seam, the anchoring element engages the inner surface of the tubing but not the seam; 
 
 lowering the plug into the tubing; 
 orienting the plug with respect to the seam; and 
 setting the plug, wherein setting the plug comprises:
 radially expanding the anchoring element to engage the inner surface of the tubing; and 
 radially expanding the seal element to engage and seal the tubing. 
 
 
   
   
     19. The method of  claim 18  wherein said orientation element comprises a radially protruding key. 
   
   
     20. The method of  claim 19  wherein said key and said anchoring element are disposed on opposed circumferential sides. 
   
   
     21. The method of  claim 18  farther comprising the step of locking the anchoring element against setting until the plug is in the desired position. 
   
   
     22. The method of  claim 18  wherein said seal element is positioned below said anchoring element. 
   
   
     23. The method of  claim 18  further comprising guiding the orientation of said plug during installation, wherein said orientation element engages the seam during installation. 
   
   
     24. The method of  claim 23  wherein said orientation element comprises a mule shoe characterized by a helical outer surface and a helical groove, wherein the helical groove engages the seam. 
   
   
     25. A method of plugging a tubing, wherein the tubing has an inner surface characterized by a longitudinal seam, comprising:
 providing a retrievable plug comprising:
 an anchoring element disposed on the plug, wherein the anchoring element is movable between an unset position with the anchoring element unexpanded and a set position with the anchoring element radially expanded; 
 a seal element disposed on the plug, wherein the seal element is compressible between a relaxed position and a radially expanded position; and 
 an orientation element for locating the position of the seam within tubing; 
 
 lowering the plug into the tubing; 
 orienting the plug with respect to the seam; 
 setting the plug, wherein setting the plug comprises:
 radially expanding the anchoring element to engage the inner surface of the tubing; and 
 radially expanding the seal element to engage and seal the tubing; and 
 
 rotating said plug until said orientation element engages said seam. 
 
   
   
     26. A method of constructing a plug assembly for use in a tubing, wherein the tubing has an inner surface along which a longitudinal seam extends, comprising:
 disposing an anchoring element on the plug assembly, the anchoring element operable to secure the plug assembly within the tubing, wherein the anchoring element is extendable from the plug assembly at a first circumferential position to engage the inner surface of the tubing at a location spaced apart from the seam; 
 disposing an orientation element configured to engage the seam and positioned on the plug assembly at a second circumferential position that is different from the first circumferential position; and 
 disposing a seal element on the plug assembly between the anchoring element and the orientation element; 
 wherein the spacing between the first and second circumferential positions is great enough such that when the orientation element engages the seam, the anchoring element engages the inner surface of the tubing but not the seam. 
 
   
   
     27. The method of  claim 26  wherein said orientation element comprises a radially protruding key, and wherein said key and said anchoring element are disposed on opposed circumferential sides. 
   
   
     28. The method of  claim 26  wherein said orientation element comprises a mule shoe characterized by a helical outer surface and a helical groove, wherein the helical groove engages the seam.